1. Field of the Invention
The present invention generally relates to a cable connector assembly, and more particularly to an Insulation Displacement Connection (IDC) cable connector assembly.
2. Description of Related Art
It is common to find the use of IDC technology in the electrical connector industry, because it allows rapid and simple connection of conducting wires to contacts without stripping nor crimping the wires. A typical IDC is made by applying a wire perpendicularly to a planar wall portion of a contact comprising a slot, such that edges of the slot cut through an insulating coating of the wire and make electrical contact with a conductor of the wire. The slots are formed by opposed edges of a sheet metal which is necessarily of a certain width to have sufficient strength to support the contact pressure against the edges.
TW patent issue No. 517895 discloses a cable connector assembly which uses IDC technology interconnecting wires and contacts contained therein for power transmission. The cable connector assembly comprises an insulative housing, a plurality of contacts, a plurality of wires, and a cover secured to the insulative housing. Each contact comprises a three-beam mating portion received in a front portion of the housing for electrically engaging with a complementary connector, and a flat insulation displacement portion defining a slot therein. Each wire comprises a conductor and an outer insulating coating. When the wire is urged into the slot of a corresponding contact, the outer insulating coating is cut by inner edges of the slot of the insulation displacement portion, thereby establishing an electrical connection between the contacts and the conductors.
However, the wires of the cable connector assembly used for transmitting power are relatively larger in the dimension thereof than wires for other usages. Therefore, once there is one wire not electrically connected with a corresponding contact reliably, the power transmission therebetween is adversely affected.
U.S. Pat. Nos. 4,410,222, 5,030,132 and 6,524,127 each disclose an IDC contact. These IDC contacts each have two slots therein to increase contact areas between each conductor and an insulation displacement portion of a corresponding contact, and to ensure the signal or power transmission between the contact and the wire.
Nevertheless, the insulation displacement portions of the IDC contacts disclosed in U.S. Pat. No. 4,410,222 are fully exposed out of an insulative housing. That is, the insulation displacement portions have no support when a flat cable is urged thereto. This may cause a deformation of the insulation displacement portions and an unreliable signal transmission between the cable and the contacts.
The insulation displacement portions of the contacts disclosed in U.S. Pat. Nos. 5,030,132 and 6,524,127 are supported by inner walls of receiving cavities defined through respective insulative housings. However, the inner walls may partly block an operator's line of sight on inserting of the wires into the dual slots. Therefore, the accuracy of the insertion of the wires is not assured.
Moreover, there is a need to have an additional structure to secure the wires to the contacts for preventing the wires inadvertently separating from the contacts after being received in the slots of the contacts. The contacts disclosed in U.S. Pat. No. 5,030,132 each comprise a pair of claws for preventing the wires from separating from the contacts. However, this complexes the structure of the contact and increases the manufacturing cost thereof.
U.S. Pat. No. 4,410,222 discloses a cable connector assembly comprising a first housing retaining the IDC contacts therein, a second housing for aligning the contacts with the flat cable, and a cover mounted to the first and the second housings for assuring the electrical connection between the flat cable and the contacts. However, the cover structure is mainly used for a flat cable, not for a single wire, and the assembly is relatively complex in structure.
A cover structure disclosed in TW patent issue No. 517895 is designed for a single wire. The cover is mounted to the housing through the engagement between recesses of the cover and protrusions formed on the housing, thereby preventing the wires from separating from the contacts. However, the protrusions are very tiny in figure, and walls of the cover are relatively thin. Thus, the engagement between the cover and the housing is not secure, the wires still has a possibility of inadvertently separating from the insulation displacement portions of the contacts and the power transmission is adversely influenced.
Hence, a cable connector assembly with improved structure for achieving a reliable transmission is needed to address the problems encountered in the related art.